Thermally spunbonded fabrics are much more effective than woven or needle punched geotextiles in preventing fine roots and rhizomes from penetrating the fabric. Heavier weight fabrics should be used for sites that do not have frequent maintenance intervals. When installing geotextiles, potentially damaging objects (i.e., large angular rocks; pointed sticks) should be removed from the site and the soil should be graded so the fabric will lay smooth and flat on the ground. Where potentially difficult to control weeds are abundant (e.g., quackgrass), an herbicide may be desirable or necessary to prevent weeds from growing to and through seams and edges from below. In some settings, a shallow trench (2"-3") around the perimeter of the installation site is helpful to hold the edges in place and keep them from becoming exposed. Seams should be overlapped 6"-8" and the fabric should be tightly fitted around any objects. Where fabrics may become exposed and subjected to vandalism they should be pinned firmly to the ground, especially around the perimeter. The fabric should then be covered with 2"-3" of mulch because ultraviolet light is damaging to most geotextiles and they should always be adequately covered. When properly installed, geotextiles will last indefinitely.
A disadvantage of using landscape fabric in shrub beds, tree wells, and other ornamental plantings is that the soil under the fabric becomes relatively inaccessible, making it difficult and time consuming to add amendments for soil improvement. However, this problem can be alleviated by adequately preparing the soil before the fabric is installed.
The following topics are discussed:
|Thermally Spunbonded is the best for weed control; it has fibers fixed in place; keeps roots from penetrating.||Needle-punched has loose threads of material that plants can easily grow through.||Woven fabrics are very strong but offer many spaces for weeds to penetrate.|
Development on Various Fabric Types
through woven fabric. Hard to remove roots
that have penetrated and woven themselves through the fabric.
With perennials, resprouting from broken roots/rhizomes/stolons will occur.
|Weeds on spunbonded
fabric; only fine hair roots have penetrated
material. Weeds are easily removed, even perennials with stolons or
|Roots of weeds
showing impact from trying to grow through spun bonded fabric. Easily
especially when growing in coarse bark.
Installations of Fabric and Mulch
|Installing a spunbonded weed control fabric.||One year later.||Three years after installation.|
|A tree well with landscape fabric, an edging, and mulch being installed around a young tree by two children on their school's landscape. See the section discussing landscape fabric for more on that topic.|
|Tree well with fabric where the mulch has completely decomposed and weeds are growing on top of (but not through) the spunbonded fabric. Tree wells, shrub beds, and other areas where fabric and bark are used must be monitored for maintenance needs and treatments applied in a timely manner. A covering of mulch is necessary to protect the fabric from UV rays and for aesthetic considerations|
Last modified: September 17, 1999
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